Wang, Shun and Lokesh, Nanjundappa and Hioe, Johnny and Gschwind, Ruth M. and Koenig, Burkhard (2019) Photoinitiated carbonyl-metathesis: deoxygenative reductive olefination of aromatic aldehydes via photoredox catalysis. CHEMICAL SCIENCE, 10 (17). pp. 4580-4587. ISSN 2041-6520, 2041-6539
Full text not available from this repository. (Request a copy)Abstract
Carbonyl-carbonyl olefination, known as McMurry reaction, represents a powerful strategy for the construction of olefins. However, catalytic variants that directly couple two carbonyl groups in a single reaction are less explored. Here, we report a photoredox-catalysis that uses B(2)pin(2) as terminal reductant and oxygen trap allowing for deoxygenative olefination of aromatic aldehydes under mild conditions. This strategy provides access to a diverse range of symmetrical and unsymmetrical alkenes with moderate to high yield (up to 83%) and functional-group tolerance. To follow the reaction pathway, a series of experiments were conducted including radical inhibition, deuterium labelling, fluorescence quenching and cyclic voltammetry. Furthermore, NMR studies and DFT calculations were combined to detect and analyze three active intermediates: a cyclic three-membered anionic species, an a-oxyboryl carbanion and a 1,1-benzyldiboronate ester. Based on these results, we propose a mechanism for the C] C bond generation involving a sequential radical borylation, " bora-Brook" rearrangement, B2pin2mediated deoxygenation and a boron-Wittig process.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | C-C; SYNTHETIC APPLICATIONS; STABILIZED CARBANIONS; ELECTRON-TRANSFER; PHOTOCATALYTIC E; Z ISOMERIZATION; BORONIC ESTERS; BOND FORMATION; Z-ALKENES; LIGHT; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Organische Chemie > Lehrstuhl Prof. Dr. Burkhard König Chemistry and Pharmacy > Institut für Organische Chemie > Arbeitskreis Prof. Dr. Ruth Gschwind |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 15 Apr 2020 05:31 |
| Last Modified: | 15 Apr 2020 05:31 |
| URI: | https://pred.uni-regensburg.de/id/eprint/27023 |
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